Primary belt drive

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Hi Gort and F.E.,
Are vented plugs necessary for belt drives. I will be installing a CNW electric start conversion kit and hadn't planned on any special venting. Maybe I need to read the instructions in the kit.
Fast Eddie said:
That’s what I use. I’ve never had any reason to suspect things were getting too hot in there.
Click to expand...
 
I have run a dry Norvil belt primary for some 20 years now and have found no reason to ventilate the primary.
That includes many long rides in the upper 90's temperatures here in the SW United States.
 
As well as 1up3down, if you read post 14, Tritonthrasher says that he’s has done huge mileage without venting. I’m running a none vented belt on a Triumph too.

Anyway, the cNw kit has some small vent slots machined into the inner cover as standard.

But if you’re unsure, just fit the vented plugs as shown by time warp, they’re a straight forward screw in addition. That’s what I’m using with my cNw primary.
 
I have to admit my T110 Triton isn’t as powerful as a Commando, so probably doesn’t generate as much heat as a Combat Norton ridden by a maniac.
 
APRRSV said:
Hi Gort and F.E.,
Are vented plugs necessary for belt drives. I will be installing a CNW electric start conversion kit and hadn't planned on any special venting. Maybe I need to read the instructions in the kit.
Click to expand...

The cNw kit includes a vented primary case.
 
460446, member: 5500"]Are you talking about holes for ventilation?
/QUOTE]


I made my own from the stock ones as a bit of an exercise. A milling machine would be better but as I don't have one I used a couple of different size hole saws to form the hole and rebate. Some stainless mesh and JB weld to complete the job.
I did make the same mistake as the manufacturer of those billet ones though as two blind holes for a peg spanner would be better than extending the slots.View attachment 14468 View attachment 14469
Click to expand...
 
gortnipper said:
Are you talking about holes for ventilation?

If so, why not something like these?

https://www.ebay.com/itm/Norton-750...t-Aluminum-BILLET-clutch-vented-/383160164637
Click to expand...

Although I'm not sure it makes any difference to have the vents I made my own from the stock ones as a bit of an exercise. A milling machine would be better but as I don't have one I used a couple of different size hole saws to form the hole and rebate. Some stainless mesh and JB weld to complete the job.
I did make the same mistake as the manufacturer of those billet ones though as two blind holes for a peg spanner would be better than extending the slots.

I've got the Norvil kit in my Commando and Dommie and happy with both.

Primary belt drive
Primary belt drive
 
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I have been using a RGM kit for the last 15 years ,fitted an Alton 6 years ago still on the original belt ,never had any problems , it's been a real fit and forget part. Unventilated even when my Norton and I lived in Western Australia for 7 years with temperatures over 40 degrees at times
 
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I run a 30 mm Maney belt drive in my well used Roadster, I cut a 30mm length out of the rubber O ring gasket between the inner and outer covers , that is the only venting I have and no issues with heat.
Maney belt drive is top quality and easy to fit.
Regards Mike
 
phippsy said:
I have been using a RGM kit for the last 15 years ,fitted an Alton 6 years ago still on the original belt ,never had any problems , it's been a real fit and forget part. Unventilated even when my Norton and I lived in Western Australia for 7 years with temperatures over 40 degrees at times
Click to expand...

Phippsy, is that run wet or dry ?
 
phippsy said:
Dry
Click to expand...

Thanks.

My reason for asking is I subscribe to the theory that oil is bad for belt drives. Even oil proof belts.

The theory is that oil picked up by the belt and pulley cannot simply be expelled through chain links, it has to be squished out at great force, and perhaps not all of it is squished out. If this kind of hydraulic situation occurs, the effective pulley size will increase, as will the belt tension.

So I subscribe to the theory that this can be a cause of belt failure, usually seen on road bikes running wet belt primary drives.
 
pierodn said:
Sorry but go to not understand.
Please can you explain what is “sorag ckutch”?.
Thsnk you
Piero
Click to expand...

Sprag clutch bearing... same as a beveldrive Ducati.

It engages in one direction to start the bike, then the elements tip over when the engine is running to free wheel.

Primary belt drive


Primary belt drive
 
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